Thanks for that link, John C. I actually was already using that to make my plans, and I used it as my guide for what to purchase. I still plan to use that to guide my installation.
The part I missed was that I had been planning to install my alarms “not interconnected” so I could put a relay and sensor on EACH alarm, so I could know which room was triggering the alarm. Only after I made my purchase did I discover that local code requires my alarms to be interconnected. So that’s the variation I was asking about. Thanks again!